Cristiano Ronaldo’s unhappy season at Manchester United continued as he remained on the bench throughout defeat to Manchester City, prompting former captain Roy Keane to accuse the club of disrespect.

The Portugal great remained a Manchester United player following a summer of speculation around his future but has started only one Premier League game this season with his only goal coming in the Europa League against Sheriff Tiraspol.

Here, the PA news agency assesses Ronaldo’s impact in his second spell with United, and how it compares to his first.

Shooting star

The final three seasons of Ronaldo’s first spell at Old Trafford, in which he hit double figures for league goals each year and peaked at 31 in 2007-08, saw him average almost six shots per 90 minutes.

That exalted figure – which he surpassed in some seasons with Real Madrid but is in line with the most prolific shooting seasons for his long-time rival Lionel Messi and exceeds any mark achieved by the likes of Harry Kane or Robert Lewandowski – translated into his goal tally, thanks to converting almost 10 per cent of his shots in both 2006-07 and 2008-09, when he scored 17 and 18 league goals respectively.

The leap past 30 in 2007-08 came on a conversion percentage of almost 18 per cent – and on 174 shots, slightly down from 180-plus in the seasons either side. In his first season back, he needed a similar conversion rate (16.4 per cent) merely to reach 18 league goals, having taken only 110 shots and barely four per 90 minutes.

He is back up to 5.2 shots per 90 in his limited involvement this season, without scoring.

Changing style

Ronaldo’s overall game has shown a marked change between leaving Old Trafford in 2009 and returning last summer.

Having made his name as a teenage winger after arriving from Sporting Lisbon, he steadily took on more of a finishing role and, after his move to Spain, evolved into an out-and-out centre-forward – and that is reflected in his level of involvement in the game and the nature of his contributions.

Having approached 2,000 total touches in 2006-07 and 2007-08, he broke that threshold in 2008-09 and averaged 2,018 touches for those three campaigns – the earliest for which such data is available on the Premier League’s official website.

Last season, by contrast, he was on the ball just 1,237 times in the league – in slightly less playing time, but the difference of around 300 minutes, or 11 per cent, from his average season before leaving is minimal compared to the near-40 per cent drop-off in involvement.

Adding in this season, 9.1 per cent of Ronaldo’s touches since returning to the club have been shots, up just slightly on 8.9 per cent over his prolific scoring seasons before leaving.

More noticeable, though, is the increase in passing which now accounts for over 70 per cent of his touches, compared to 58.5 per cent before his departure. The combined figure is up from 67.4 per cent to 79.9 per cent, perhaps reflecting a decrease in dribbling since moving to a central role.

Influence

Ronaldo’s goals gained United 14 points last season, almost a quarter of their 58-point total and a tally exceeded only by his 31-goal season 14 years previously when his efforts were worth 19 points.

He scored almost 42 per cent of United’s 57 league goals, breaking 40 per cent for the second time after 2007-08, and his effect on their win percentage was striking.

United won 14 of Ronaldo’s 27 starts, 51.9 per cent – and while that percentage is the lowest of Ronaldo’s United career, their win ratio dropped all the way to 18.2 per cent in the games he did not start. They averaged 1.70 points per game with him in the XI, compared to 1.09 without.

Starting on the bench in the wins over Liverpool, Southampton, Leicester and Arsenal sets up a different story in the early stages of this season and Keane pulled no punches after the derby loss.

“I think Man United are just showing disrespect to Ronaldo,” he told Sky Sports. “I think he should have been let go before the transfer window. You don’t hold on to Ronaldo to sit on the bench. He’s one of the greatest players ever.”